body, html {
  margin: 0;
  padding: 0;
}
img {
  width: 100%;
}
ul, li {
  margin: 0;
  padding: 0;
  list-style: none;
}

.left-menu {
  position: fixed;
  top: 0;
  left: 0;
  width: 200px;
  height: 100%;
}
.top-nav, .teacher-list {
  margin-left: 200px;
}
.top-nav {
  
}
.teacher-list {

}
.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,.5);
}
.modal img {
  width: 60%;
}
